Nitrogen and phosphorus removal by periphyton from agricultural wastes in artificial streams

Dissolved nutrient concentrations were rapidly reduced in slow moving I wat ers by the periphyton growing in shallow experimental streams. Nutrients ad ded after an initial decrease were removed at a faster rate by the well dev eloped periphyton community. Biomass of 36.2 g DW.m(-2), 23.7 g AFDW.m(-2) end 100 mg Chl.m grew m a high phosphorous loaded stream, while 31.7 g DW.m (-2), 16.6 g AFDW.m(-2) and 42 mg Chl.m(-2) were determined in a low loaded stream. The two different nutrient concentrations also generated quite dif ferent qualitatively biotic communities from identical origin. Stigeocloniu m tenue dominated in both systems, but Cyclotella spp., Epithemia spp., and Synedra spp. occurred in different proportions.